This invention relates to a device for transferring flat objects, for instance film cards, between two stations featuring a transport mechanism for transporting the objects from one station to the other. Both stations are provided with two guides for lateral guidance of the objects.
Devices of this kind may, for instance, be microfilm readers, with one station being a film card magazine, and the other station a film card holder. The film card to be read is automatically pulled out of the film card magazine, transported onto the film card holder, and returned automatically into the respective compartment of the film card magazine after use. As an example of the state of the art reference be made to West German Offenlegungsschrift No. 32 43 172.4.
A typical film card magazine is a box-like structure divided into compartments by partitions. Each film card is stored in one compartment. A typical film card holder is a flat surface with an opening corresponding to a single frame on the film disposed between a source of illumination and the optics of the film reader. There is usually a flat glass plate superimposed over the holder to sandwich the film card between the holder and the glass plate, the glass plate being hingedly mounted or otherwise movable with respect to the holder in order to insert and remove the film card from the holder.
Since it is desirable to design the film card magazine as small as possible, it is necessary to keep the height of the openings of the individual compartments accomodating the film cards at a minimum. If these openings become too small, however, it is rendered impossible for the film cards to be reliably inserted into the respective compartments, because they hit against the compartment partitions or against the faces of the neighboring film cards in case the latter are not exactly even but, for example, warped so that they are undulated.
Certain film cards, in particular thermally developed films (vesicular films) tend to form considerable surface undulation. A factor leading to even further undulation rests with the typical film card holder of the type which opens, since the advance of the film card is initially obstructed by the glass plate of the film card holder moving upwards. Even with compartments featuring relatively wide openings, such film cards hit against the faces of the neighboring film cards in the film card magazine, and can hence not be inserted into the film card magazine.
Of course, provision could be made of a funnel-type guiding passage between the film card holder and the film card magazine through which the film cards are to be guided, with said guiding passage narrowing towards the film card magazine. This would, however, have the disadvantage of the film cards being easily damaged by scratching.
The above problems are of course not only present with film cards, but they are posed each time flat object-carriers which are prone to deformation are inserted into a narrow slot.